PFO Device

ABSTRACT

A medical device for treating a PFO is presented as well as a mechanism for its delivery, repositioning and/or removal. The device includes a wire or cable framework of six shape-memory cables formed into a right side having six loops that support a right side sail and a left side having six loops that support a left side sail. The right side loops and left side loops are connected together via waist members that extend between the right side and left side loops. Each cable is threaded through a through hole of a central post and pass through one of each of four connecting collars that establish the basic shape of the PFO device and retain the cables together to form a flexible and resilient PFO device.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S.application Ser. No. 17/558,898, filed on Dec. 22, 2021, the entirecontents of which are incorporated herein by reference.

FIELD OF THE INVENTION

Embodiments of the present disclosure relate generally to an occlusiondevice for closing an aperture in a biological structure and moreparticularly for closing a conduit or aperture in a heart wall, such asa defect between atrial chambers, as well as for methods and systems fordeploying, repositioning and retrieving occlusion devices.

BACKGROUND OF THE INVENTION

The heart is comprised, generally, of four chambers: the left and rightatria and the left and right ventricles. Separating the left and rightsides of the heart are two walls or “septa”. The septa are susceptibleto a number of types of defects, including patent foramen ovale, atrialseptal defects and ventricular septal defects. Although the causes andphysical characteristics of these defects vary by type, they generallyinvolve an opening (e.g. an aperture, slit, conduit, flap-coveredaperture) through the septum that allows blood to shunt between chambersin the heart in an abnormal way that compromises the performance of theheart and circulatory system and has disadvantageous healthconsequences.

Normally, permanently repairing septal or other cardiac defects requiresopen heart surgery; a high risk, painful and costly procedure. Inresponse to these concerns, modern occlusion devices have been developedto treat certain septal defects. Rather than surgery, these occlusiondevices are small enough to be deployed by inserting a catheter into amajor blood vessel and moving the occlusion device through the catheter.This type of procedure can be performed in a cardiac cathlab, and avoidsmuch of the risks, cost, and pain associated with open heart surgery.Such occlusion devices can be used to treat a wide range of cardiacdefects, including patent ductus arteriosus, patent foramen ovale (PFO),atrial septal defects, ventricular septal defects, and can be used toocclude other cardiac and non-cardiac apertures.

One type of occlusion device generally has a first side, which ispositioned on one side of the defect, a second side, which is positionedon the opposite side of the defect, and a center section, which extendsthrough the center of the defect. Since defect size varies from patientto patient, it is a challenge to center the center section within aparticular defect, which is often essential to ensuring that the defectis optimally occluded. This is important because if the defect is notproperly occluded, blood may continue to shunt through the defectlessening the effectiveness of the occlusion device. Known occlusiondevices address the problem of variable centering in a variety of ways,such as for example through the use of articulated center posts or theuse of flexible spring connector that extends between the sides, such asrespectively described in U.S. Pat. No. 7,087,072, filed on Jan. 22,2003; and U.S. Pat. No. 7,972,361, filed on Jun. 19, 2006; the entirecontents of both of which are incorporated herein by reference.

Furthermore, many occlusion devices are designed so that the first andsecond sides are collapsible, allowing the occlusion device to fitinside a catheter. A catheter with a small diameter reduces trauma,improves maneuverability, and allows the occlusion device to be used invery young patients or in those who have a small vasculature. Therefore,it is desirable that the occlusion device be highly compact when in acollapsed position so that the smallest diameter catheter may be usedfor deployment.

Also, in the event the device is not optimally deployed initially, it isdesirable that it is easily retrievable, so that the procedure may beperformed again. While some types of occlusion devices are retrievablevia catheter, many require open heart surgery to be retrieved. Even ininstances where the occlusion device can be retrieved using a catheter,a different catheter with a larger diameter may be required forretrieval because the device may not readily resume the compact shape ithad before deployment. Furthermore, once retrieved, the device may becompromised from the stress of withdrawing it back into the catheter,even if a larger diameter catheter has been used. As such, it may not bepossible to reuse the retrieved occlusion device.

Thus, there is a need in the art for an occlusion device that is easilyloaded into a catheter, and that can be retrieved, reloaded, andredeployed in situ. There is also a need in the art for an occlusiondevice which has a centering system to improve the ability of the deviceto be centered in the defect.

SUMMARY

Embodiments of a PFO device disclosed herein are comprised of six wirecables made from a super-elastic material that are threaded through acenter post. Each of the six cables has ends that are mated together ina set of terminal connector collars. Each cable is routed andinterleaved through additional groups of collars forming a set of loops.The loops are heat set to form a pair of opposed disk shapes whose loopssupport sail structures on each side of the device. It is the uniquecollar locations that control the shape of the loops.

This construction permits stresses imposed on the device to be sharedacross the device therefore reducing stress concentrations on eitherside of the device, and thereby making the device closely conform to theanatomy of the patient, thus improving performance of the device. Thesail structure is continuous and completely covers the left side loopsand is intermittent and interleaved on the right side. The center postis used for deployment and resides on the right side and the device isdelivered through a catheter positioned in the right heart via aSeldinger or similar procedure.

When the PFO device is deployed through the PFO in the heart, theslightly smaller left sail resides in the left atrium and the slightlylarger right sail is deployed in the right atrium. At least the leftsail is provided with a low profile and smooth surface to minimize thechance of blood clot formation.

The PFO device is resiliently deformable through a range of positionsfrom a collapsed, delivery shape that fits within a delivery catheter toan expanded, deployed configuration, with the wire loop supported sailsradiating generally outward to sandwich tissue therebetween. The deviceis biased into the deployed configuration by way of the shape-memorymaterial form which the wire loops are constructed. The distance betweenthe frame-supported sails, as well as the various angles at which theymay engage the opposed sides of the septum around the PFO is variable byway of the flexibility imparted to device by the wire construction.

These and other unique features provide for embodiments of thedisclosure that provide PFO devices, which are highly adaptable for usein a variety of anatomies and which are resilient to the potentialstrains of loading, deployment and repositioning.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of an embodiment of a PFO device shownin stretched or slightly elongated state as if pulled in opposinglongitudinal directions for illustrative purposes.

FIG. 2 is a proximal/right side perspective view of the embodiment shownin FIG. 1 .

FIG. 3 is schematic diagram showing the distribution and arrangement ofcollars along a loop wire of the type shown in FIGS. 1-2 .

FIG. 4 is a schematic diagram illustrating part of the assembly processfor making the PFO device shown in FIGS. 1-3 .

FIG. 5 is a proximal/right side view of the PFO device shown in FIGS.1-2 , illustrating the right side sail.

FIG. 6 is a partial, perspective view of the right side sail shown inFIG. 5 , illustrating the group I collars used to form the sail's loopsand provide securement areas for retention of the sail material.

FIG. 7 is a distal/left side view of the PFO device shown in FIGS. 1-2 ,illustrating the left side sail.

FIGS. 8-13 are a series of side perspective views showing the deploymentsequence for deploying the PFO illustrated in FIGS. 1-2 through a PFO ofa septum of the heart via a delivery catheter.

FIGS. 14-17 are a series of side perspective views showing the sequencefor retracting the deployed PFO device shown in FIG. 13 back into adeployment catheter for removal or repositioning.

DETAILED DESCRIPTION

An exemplary embodiment of a PFO device 10 is shown in FIGS. 1 and 2 .The device 10 is illustrated slightly stretched from its nominal shapeby being pulled apart as indicated by force arrow 12 and force arrow 14.Seen in this stretched configuration there is a left sail 16 on the leftside 18 and a right sail 20 on the right side 22.

Note that throughout, the terms “right” and “left” are used forconvenient reference and are selected in accord with the orientation ofthe device as it would typically be situated in the heart and in accordwith typical cardiac terminology for distinguishing the sides of theheart. These terms should not, however, be considered limiting.

Device 10 includes a central waist region 24, which has a reduceddiameter relative to the left side and right side sails 16 and 20, andis the portion of the device 10 which sits in the PFO 100 of the Septum102 after deployment, such as in the manner shown in FIG. 13 (with thePFO 100 visible in FIGS. 8-11 ).

In the embodiment shown, the device 10, is made up of a series of wirecables 26. The cables 26 may be constructed of a single wire or strandedwire. In the embodiment shown, the PFO device is constructed of sixcables 26. Cables 26 are preferably subjected to precise pre-shaping togive them a “shape memory” so that the PFO device 10 will be biased tomaintain and resume after deployment from the confines of a deliverycatheter. The pre-shaping can be done using any suitable method, such asmachining, heat treating, or both.

In at least one embodiment, the cables 26 are at least partiallyconstructed from multiple strands of one or more shape memory metals oralloys such as Nitinol. The cables 26 make up a framework 27 comprisedof loops 28, which support the left sail 16 and right sail 18; and waistmembers 30 which extend from the loops 28 at either side 18 and 22 ofthe device to define the comparatively more narrow waist region 24.

The diameter of the cables 26 must be small enough so that the loops 28which support the sails 16 and 20 are flexible enough to collapse whenthe device 10 is being loaded or retrieved. However, the cables 26 mustbe stiff enough to allow the loops 28 to lie as flat possible againstthe patient's septum with the waist members 30 biasing the loops 28 ofthe opposing sides 18 and 22 toward each other to create an effectiveseal against tissue of the septum around the PFO.

The precise shape of the loops 28 as well as the tendency for the waistmembers 30 to pull the sides 18 and 22 together is also provided by heator machine shaping so that the loops 28 have shape memory to ensure thatthe loops 28 resume their proper deployed shape once the loops 28 leavethe catheter such as in the manner shown in FIGS. 8-13 .

Another advantage of pre-shaping the loops 28 using heat is to ensurethat the loops 28 are properly sized. If the loops 28 are too large ortoo small for the device 10, the loops 28 may pucker or may cause thesails 16, 20 to pucker.

The programed shape and flexibility of the cables 26 allow the device 10to have left and right sides 18, 22 which will not only tend to hug thetissue surrounding the PFO or other tissue opening or defect throughwhich the device 10 is deployed (thereby creating a uniform seal aroundthe opening), but also to reduce the potential for increased pressure onthe surrounding tissue that might otherwise be caused by larger and/orstiffer structures such as are commonly used in some known devices. Inthe PFO device 10 shown, the support hoops 28 in combination with thewaist members 30 help distribute pressure more evenly around acontinuous circle, decreasing the possibility that increased pressurewill be exerted at any one contact point. By distributing pressure moreevenly, the risk that any part of one or more of the cables 26 willirritate or abrade septal tissue or is greatly reduced.

The sails 16, 20 are a mesh or woven fabric preferably formed of amedical grade polymer. In at least one embodiment the sails 16, 20 areat least partially constructed of Polyester. In at least one embodiment,the sails 16, 20 are at least partially constructed from a high densitypolyvinyl alcohol (PVA) foam, such as that offered under the trademarkIVALON®. To minimize the chance of the device 10 causing a blood clot,the sails 16, 20 may be treated with a thrombosis-inhibiting material.One such suitable material is heparin.

In at least one embodiment the left sail 16 is a multilayer structurehaving a base layer 17 and external layer 19. The external layer 19completely covers the loops 28 of the framework 27 with base layer 17extending from the external layer 19 to secure the external layer 19 tothe underlying left side 18 loops and loops 28 via sutures 42.

In at least one embodiment, such as is shown in FIG. 7 , the externallayer 19 and base layer 17 is a single unitary piece of continuousmedical grade polyester.

In at least one embodiment, such as is shown in FIGS. 5-6 the right sidesail 20 is interwoven between the cables 26 that make up the loops 28 onthe right side 22.

Though the shape memory aspect of the cables 26 does provide the device10 with its deployed state shape and the mechanical requirement tomaintain that deployed state shape despite external distortion forcedupon the device (such as by loading it into a catheter), the initialarrangement of the cables 26 relative to each other in order establishthe basic configuration of the framework 27 is provided by a pluralityof collars 32 and a central post 34.

In at least one embodiment, one or more of the collars 32 and/or thecentral post 34 is at least partially constructed of a radiopaquematerial or includes a radiopaque coating.

The central post 34 is provided with six through holes 36 (visible onlyin FIG. 4 ) through which each of the six cables 26 is passedtherethrough. A plurality of four categories of collars 32 a, 32 b, 32c, and 32 d connecting various regions of the six cables 26 to oneanother in order to form loops 28 and secure the ends 38 (visible inFIGS. 3-4 ) of the cables 26 together.

First group collars 32 a form and hold the loops 28 of the right side 22at the periphery of the sail 20. The manner in which of first groupcollars 32 a are utilized is shown in FIGS. 5-6

Second group collars 32 b connect adjacent waist members 30 at thecentral waist region 24 such as in the manner shown in FIGS. 1-2

Third group collars 32 c connect adjacent cable extensions 38 (visiblein FIGS. 3 and 4 ) on the left side 18 of the device 10, along theperiphery of the left sail 16 such as in the manner shown in FIG. 7 .

Fourth group collars 32 d join the free ends 40 of the cable extensionswithin the framework interior such as in the manner shown in FIG. 2 .

In at least one embodiment the PFO device 10 is comprised of a total oftwenty four collars 32 a, 32 b, 32 c, and 32 d. As indicated above, eachcable 26 passes through a single hole 36 in the central post 34. Eachcable 26 is crimped in the central post and therefore anchored in thecentral post 34 forming extensions 38 extending from the opposedopenings of the hole 36.

To illustrate the manner in which the framework 27 is assembled,schematic illustrations of the manner in which a single cable 26interacts with the central post 34 and the four types or regions ofcollars 32 a, 32 b, 32 c, and 32 d is shown in FIG. 3 . In FIG. 4 twocables 26 are shown with the four classes of collar illustrated and theorder of cables 26 which they engage based on their relative arrangementas dictated by the six holes 36 of the central post 34. Additionalcables are added to the framework 27 in accordance with the patternshown.

With reference to FIGS. 3-4 , when the framework 27 is viewed as a wholesuch as in the manner shown in FIG. 2 , it can be seen that eachextension 38 of a cable 26 passes though one collar of each of the fourgroups 32 a, 32 b, 32 c, and 32 d, joining up with its complementaryends 40 at termination collar 32 d. Thus, each individual cable 26 formsextensions 38 that is in turn formed in to a continuous member of theframework 27. The extensions 38 are inter-woven through the collars 32a, 32 b, 32 c, and 32 d to form twelve petals or loops 28. Six loops 28support the fabric of the left sail 16 and six loops 28 support thefabric of the right sail 20. The fabric sails 16 and 20 are stitched tothe cables 26, on the left and right side 18, 22 of the PFO device 10via sutures 42.

In some embodiments, it may aid in securement of the respective leftsail 16 and right sail 20, sutures 42 may be threaded through or simplybiased against the collars 32 c and 32 a respectively.

As a result of this unique framework construction, forces are applied tothe device 10 by heart motion are shared across the device from the leftside and the right side. Unlike many previous PFO devices, the left andright sides 18 and 22 of the device 10 do not function independently butrather they are (and act as) a unitary structure sharing stress andspreading it over a large area which is beneficial.

As indicated above, the PFO device 10 may be used to address variousopenings or defects in tissue, and is especially suited for addressingthe presence of a PFO in the septum of a mammalian heart. An exemplaryprocedure showing the delivery of the PFO device 10 from a catheterassembly 50 through a PFO or opening 100 of a septum 102 is shown inFIGS. 8-13 .

In FIG. 8 a catheter assembly 50 into which the PFO device 10 has beenloaded in a compressed or unexpanded state is shown being advancedthrough the PFO 100 of the septum 102.

At FIG. 9 , the PFO device 10 is advanced out of the catheter assembly50 to allow the left side 18 of the PFO to self-expand.

At FIGS. 10 and 11 PFO device 10 continues to be advanced out of thecatheter assembly 50 and self-expand. The catheter assembly 50 is pulledback to allow the expanded left side 18 of the PFO device to be seatedagainst the septum 102.

At FIG. 12 the delivery tool 52 and the catheter assembly 50 is shown.The delivery tool 52 is an elongated shaft that extends the length ofthe catheter assembly 50 and which incudes at its distal end 54 anactuatable retaining clamp 56 that is actuatable (via an actuationmechanism such as a button or trigger located at the proximal end of thetool (not shown)) between a closed position shown in FIG. 12 and an openposition shown in FIG. 13 .

The central post 34 includes a retaining knob 44 (visible in FIG. 13 )which the retaining clamp 56 engages while the PFO device 10 during thedelivery process.

The delivery tool 52 is movable relative to the catheter assembly 50 andby its advancement the PFO device 10 is advanced out of the catheterassembly 50 such as in the manner described above.

Once the left side 18 is seated against the septum 102 in the mannershown in FIGS. 10 and 11 , the right side 22 is advanced out of thecatheter assembly 50 and allowed to self-expand and seat against theseptum 102 as well. While the PFO device 10 remains engaged to thedelivery tool 52, the user may manipulate the tool 52 and the PFO deviceto assist in ensuring that the PFO device is properly positioned againstthe septum 102. Once properly positioned the PFO device 10 is releasedfrom the delivery tool by actuation and opening of the retaining clamp56 such as in the manner shown in FIG. 13 . Once the PFO device 10 isdeployed the catheter assembly 50 is withdrawn from the patient.

In some cases, it may be necessary to reposition or remove the PFOdevice 10 from its original delivered position, such as is shown in FIG.13 . In that case, the catheter assembly 50 remains in place or isreintroduced as necessary. Once back in position adjacent to thedeployed PFO device 10, the delivery tool 52 is advanced from theassembly 50 and recaptures the device 10 via actuation of the retainingclamp 56 onto the retaining knob 44.

Once the PFO device 10 is re-engaged by the delivery tool 52 (nowfunctionally a capture tool), the PFO device 10 is pulled back into thecatheter assembly 50 in the manner shown in FIGS. 14-17 . Because of theextremely flexible nature of the framework 27 cables 26 and the device'sprogramed shape memory, the PFO device 10 can by repeatedly compressedback into its unexpanded state within the confines of the catheterassembly 50, and re-delivered to the same or a new location as necessarywithout harming the structural integrity of the device.

The many features and advantages of the invention are apparent from theabove description. Numerous modifications and variations will readilyoccur to those skilled in the art. Since such modifications arepossible, the invention is not to be limited to the exact constructionand operation illustrated and described. Rather, the present inventionshould be limited only by the following claims.

What is claimed is:
 1. A self-expanding PFO device having a confinedstate and an expanded state, and having a left side and a right side anda waist region therebetween, the device comprising: a central post, aplurality of cables, a plurality of collars, a left sail and a rightsail, the central post being located on the right side, the central postdefining a plurality of through holes, the plurality of through holesbeing equal to the plurality of cables, each of the plurality of cablespassing through one of the plurality of through holes, each of theplurality of cables having a pair of ends, the left side sail and theright side sail each having a periphery, each of the plurality of cablespassing through four collars of the plurality of collars, to form sixloops on the right side, six loops on the left side and six waistmembers extending between the six loops on the right side and the sixloops on the left side; a first of the four collars connecting two ofthe plurality of cables along the periphery of the right sail to formone of the six loops on the right side; a second of the four collarsconnecting two of the plurality of cables at the waist region to formone of the six waist members; a third of the four collars connecting twoof the plurality of cables along the periphery of the left sail to formone of the six loops on the left side; a fourth of the four collarscollars connecting the pair of free ends of one of the plurality ofcables.
 2. The PFO device of claim 1, wherein in the confined state thedevice is folded into the interior of a catheter assembly.
 3. The PFOdevice of claim 2, wherein the plurality of cables are constructed of aplurality of strands of shape memory material.
 4. The PFO device ofclaim 3, wherein the shape memory material is nitinol.
 5. The PFO deviceof claim 4, wherein at least one of the right side sail and left sidesail are constructed of medical grade polyester.
 6. The PFO device ofclaim 5, wherein the left side sail completely covers the six loops onthe left side.
 7. The PFO device of claim 5, wherein the right side sailis interwoven between the cables of the six loops on the right side. 8.The PFO device of claim 1, wherein the right side and left side have adiameter greater than the waist region.
 9. The PFO device of claim 8,wherein the left side has a diameter less than the diameter of the rightside.